Evaluation of a Fire Risk Index Method for Multistorey Apartment Buildings Hultquist, Hans

74 Pages·2017·5.2 MB·English

Evaluation of a Fire Risk Index Method for Multistorey Apartment Buildings
Hultquist, Hans; Karlsson, Björn
2000
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Citation for published version (APA):
Hultquist, H., & Karlsson, B. (2000). Evaluation of a Fire Risk Index Method for Multistorey Apartment Buildings.
(LUTVDG/TVBB--3088--SE; Vol. 3088). Department of Fire Safety Engineering and Systems Safety, Lund
University.
Total number of authors:
2
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LUND UNIVERSITY
PO Box 117
221 00 Lund
[phone]
Evaluation of a Fire Risk
Index Method for Multi-
storey Apartment
Buildings

Hans Hultquist
Björn Karlsson

Department of Fire Safety Engineering
Lund University, Sweden

Brandteknik
Lunds tekniska högskola
Lunds universitet

Report 3088, Lund 2000

Research funded by Nordic Wood, NUTEK and SBUF

Evaluation of a Fire Risk Index Method for
Multi-storey Apartment Buildings

Hans Hultquist
Björn Karlsson

Lund 2000

Evaluation of a Fire Risk Index Method for Multi-storey Apartment Buildings

Hans Hultquist
Björn Karlsson

Report 3088
ISSN: 1402-3504
ISRN: LUTVDG/TVBB--3088--SE

Number of pages: 67
Illustrations: Hans Hultquist

Keywords
Standard QRA, quantitative risk analysis, index method, semi-quantitative index method, FRIM-MAB,
mean risk, risk profile, fire risk, multi-storey apartment buildings.

Abstract
A need for methods to assess fire risks in timber frame buildings lead to the development of FRIM-
MAB, a Fire Risk Index Method for Multi-storey Apartment Buildings. The main objective of this
report is to evaluate this method against a different risk analysis method, in this case a standard QRA
(quantitative risk analysis) based on an event tree.

Four different multi-storey apartment buildings in the Nordic countries were analysed in this study. The
QRA resulted in a certain ranking of the four buildings with respect to fire risk. The Fire Risk Index
Method was then used to analyse the same buildings. Three slightly different approaches were used to
arrive at a fire risk index for each building. The Index Method results gave exactly the same ranking as
the quantitative risk analysis for all three approaches. The conclusion of the analysis is therefore that
FRIM-MAB seems to work reasonably well for multi-storey apartment buildings, but further studies
are recommended to confirm this.

© Copyright: Brandteknik, Lunds tekniska högskola, Lunds universitet, Lund 2000.

Brandteknik Department of Fire Safety Engineering

Lunds tekniska högskola Lund University

Lunds universitet P.O. Box 118

Box 118 SE-221 00 Lund

221 00 Lund Sweden

[email protected] [email protected]
http://www.brand.lth.se http://www.brand.lth.se/english

Telefon: 046 - 222 73 60 Telephone: [phone]

Evaluation of a Fire Risk Index Method for Multi-storey Apartment Buildings Summary

Summary

The second phase of the Nordic Wood project “Fire-Safe Wooden Houses” has been
running since 1997. The project is divided into three main areas:

i. Strategic knowledge
ii. Technical knowledge and methods
iii. Development of products and systems

The project “Fire Risk Assessment” was formed as a sub-project to “Strategic
knowledge”. The need for new and better fire risk assessment methods resulted in the
work to produce a semi-quantitative index method, the Fire Risk Index Method for
Multi-storey Apartment Buildings (FRIM-MAB). In this report FRIM-MAB is referred to
simply as the Index Method.

Earlier reports have described the development of the Index Method. The purpose of
this report is to get some idea of the validity of the method. Work was therefore
carried out to compare it against other risk analysis methods, that have some bases in
accepted fire design methods. However, in many cases there are no accepted fire
design methods available. For example, firestops at joints, intersections and concealed
spaces are very important in timber-frame buildings, but there is no method available
to calculate or numerically compare different design solutions in this respect. The
evaluation can therefore only result in some indications on validity and is to a
considerable extent based on subjective judgement.

The comparative methodology used is a standard quantitative risk analysis (QRA)
based on an event tree. The analysis resulted in two rankings of the buildings
analysed, one from FRIM-MAB and one from the standard QRA. These rankings
were compared and some conclusions drawn on how well FRIM-MAB operates.

The events in the QRA event trees for the analysed buildings were flaming fire, fire
detected automatically, occupant suppressing, sprinkler failure, door open, location of
occupants, flashover and spread, level and asleep. All or some of these events make
up the event trees. The standard QRA resulted in a number of risk profiles and a
ranking based on the expected number of people exposed to critical conditions given a
fire.

Four existing timber-frame buildings were analysed, one in Sweden (Wälludden), one
in Norway (Einmoen), one in Denmark (Casa Nova) and one in Finland (Viikki). The
result from FRIM-MAB and from the QRA resulted in the same fire risk ranking,
where the Vikki building had the lowest risk and the Casa Nova building the highest.

The main conclusions that can be drawn from this analysis is that the Index Method
ranks the buildings analysed in the same order as the very different QRA method.
This indicates a certain validity and shows that the Index Method can be a very useful
tool, although no proof of validity can be given. More work is recommended, where
existing buildings are analysed and the method developed further.
Evaluation of a Fire Risk Index Method for Multi-storey Apartment Buildings Summary
Evaluation of a Fire Risk Index Method for Multi-storey Apartment Buildings Table of contents

Table of contents

1 INTRODUCTION............................................................................................................................4
1.1 BACKGROUND.............................................................................................................................4
1.2 OVERVIEW OF THIS REPORT........................................................................................................4
2 METHODOLOGY...........................................................................................................................6
2.1 GENERAL....................................................................................................................................6
2.2 STANDARD QRA.........................................................................................................................7
2.3 DIFFICULTIES USING SUGGESTED TOOLS ON A MEDIUM-RISE APARTMENT BUILDING..................7
3 APARTMENT BUILDINGS ANALYSED..................................................................................10
3.1 GENERAL QUALITATIVE DESIGN REVIEW (QDR).....................................................................10
3.2 SPECIFIC ON EACH BUILDING.....................................................................................................11
4 EVENTS IN THE EVENT TREE.................................................................................................14
4.1 INITIAL FIRE LOCATION?...........................................................................................................14
4.2 FLAMING FIRE?.........................................................................................................................14
4.3 FIRE DETECTED AUTOMATICALLY?...........................................................................................14
4.4 OCCUPANT SUPPRESSING?........................................................................................................15
4.5 SPRINKLER FAILURE?................................................................................................................15
4.6 DOOR OPEN?.............................................................................................................................15
4.7 LOCATION OF OCCUPANTS?.......................................................................................................15
4.8 LEVEL?.....................................................................................................................................16
4.9 FLASHOVER AND SPREAD?........................................................................................................16
4.10 ASLEEP?....................................................................................................................................17
5 RESULTS FROM THE STANDARD QRA.................................................................................18
5.1 SENSITIVITY ANALYSIS.............................................................................................................19
6 INDEX METHOD VERSION 1.2.................................................................................................20
6.1 GENERAL..................................................................................................................................20
6.2 THREE DIFFERENT RISK INDICES...............................................................................................20
6.3 RESULTS...................................................................................................................................22
7 COMPARISON BETWEEN INDEX METHOD AND STANDARD QRA..............................24
8 CONCLUSIONS.............................................................................................................................26
REFERENCES.....................................................................................................................................28
Appendix A Evacuation calculations...............................................................................................................30
Appendix B HAZARD scenario......................................................................................................................32
Appendix C Event trees for analysed buildings...............................................................................................34
Appendix D Full version of Index Method.......................................................................................................38
Appendix E Detailed parameter definitions.....................................................................................................58
Appendix F Index Method results....................................................................................................................60
Appendix G Comments given on using the Index Method...............................................................................62
Appendix H Comparison with concrete building.............................................................................................64